Reach further terminal positions on your Ariston condensing boiler with the genuine Ariston Coaxial Extension (part number 3318465), a 2000mm length of 60/100mm coaxial pipe designed to lengthen the flue run on horizontal or vertical balanced-flue installations. It shares the same concentric twin-wall construction as the boiler's original flue kit, carrying combustion air in through the outer 100mm sleeve while exhaust gases vent through the inner 60mm pipe, so the whole run stays fully sealed and weatherproof from boiler to terminal.
This 2000mm extension is the longest single piece in Ariston's 60/100 coaxial flue accessory range, sitting alongside the 500mm (3318078) and 1000mm (3318077) extensions for installations that need to cover greater distances with fewer joints. It uses the same push-fit connection as the rest of the range, so it slots straight into an existing coaxial run without cutting, sealant or extra fixings.
60/100mm
Coaxial Diameter
Gas Safe
Install Requirement
Gas Safe Installation Required
This flue extension forms part of a balanced flue system on a gas-fired appliance and must only be fitted by a Gas Safe registered engineer. The completed flue run must meet the boiler manufacturer's maximum permitted flue length and terminal clearance requirements before commissioning.
Concentric Twin-Wall Design
Combustion air is drawn in through the outer pipe while exhaust gases vent through the inner pipe, keeping the balanced flue system sealed along its full length.
Simple Push-Fit Jointing
Connects to Ariston coaxial flue components using a push-fit joint, allowing the flue run to be extended without cutting, gluing or additional brackets.
2000mm Extension Length
Adds a full two metres to the flue run in a single piece, reducing the number of joints needed on longer horizontal or vertical installations.
60/100mm Coaxial Sizing
Matches the 60/100mm diameter used across Ariston's core condensing boiler range, keeping flue resistance and terminal clearances consistent with the original kit.
Horizontal and Vertical Use
Suitable for extending both horizontal balanced-flue kits and vertical roof-terminated coaxial systems on compatible Ariston boilers.
Weatherproof White Finish
Finished in white to match Ariston's standard coaxial flue components for a neat, consistent appearance on exposed external runs.
Check Maximum Flue Length Before Fitting
Adding a 2000mm extension uses up a significant portion of most Ariston boilers' maximum permitted flue length in one piece. Always check the flue length table in your specific boiler's installation manual, accounting for any elbows or bends already in the run, before combining this extension with other coaxial components. This extension is built for the 60/100mm coaxial range and is not interchangeable with the 80/125mm or twin 80mm flue systems used on some other Ariston models.
General
Product Type
Coaxial Flue Extension
Flue System
Diameter
60/100mm (coaxial)
System Type
Balanced flue / room-sealed
Suitable Orientation
Horizontal or vertical
Compatibility
Compatible Flue Range
Ariston 60/100mm coaxial flue accessories
Typical Boiler Ranges
E-Combi, E-System, Clas HE, Genus HE, Microgenus HE (60/100 flue models)
Installation
Must be fitted by a Gas Safe registered engineer
Fewer Joints Over Long Runs
Using a single 2000mm extension instead of multiple 500mm or 1000mm sections reduces the number of push-fit joints in the flue run, which can simplify installation on boilers sited well away from a suitable wall or roof terminal position.
Which Ariston boilers is the 3318465 extension compatible with?
It is designed for Ariston condensing boilers fitted with the 60/100mm coaxial flue system, including models across the E-Combi, E-System, Clas HE and Genus HE ranges. Always check your specific boiler's installation manual to confirm it uses the 60/100mm coaxial flue before ordering.
Can this extension be used on a vertical flue run?
Yes. The 3318465 extension can be used on both horizontal coaxial kits and vertical roof-terminated systems, in combination with the appropriate vertical starter and vertical flue terminal components.
Will a 2000mm extension exceed my boiler's maximum flue length?
It might, depending on the model and what else is already fitted in the run. Every extension, elbow and bend counts towards the boiler's maximum permitted flue length, so always check the flue length table in your boiler's installation manual before adding this extension.
How does it connect to the existing flue?
It uses a push-fit coaxial joint that connects directly to other Ariston 60/100mm flue components, so no cutting or sealant is required. Installation should still only be carried out by a Gas Safe registered engineer.
Is there a shorter version of this extension?
Yes. Ariston's 60/100mm coaxial range also includes a 500mm extension (3318078) and a 1000mm extension (3318077), allowing the flue run to be extended in smaller increments where a full 2000mm section isn't needed.
